Extension ladders are normally supported in an upright position at their upper ends by the vertical wall of a building or the like and at the bottom end on the ground surface. The ground surface may be irregular such that only one lower end of the two ladder rails engage the ground thus making the ladder unsafe. Even if both rail lower ends engage the ground there may be slippage away from the vertical surface causing the ladder to fall and making it dangerous and unsafe.
There have been auxiliary leg structures for step ladders but these ladders do not rest against a vertical wall surface or the like at the upper end of the ladder. These legs are also positioned high up on the ladder thereby substantially changing the ladder's operation.